Determination Method for Ractopamine in Swine and Cattle Tissues Using LC/MS

Abstract

Simple and reliable methods using LC/MS have been developed for the determination of the b-agonist ractopamine in swine and cattle tissues. Ractopamine was extracted with ethyl acetate from muscle and liver, and the ethyl acetate layer was evaporated to dryness. The residue was purified by partition with acetonitrile/n-hexane. In the case of fat, ractopamine was extracted and purified by partition with acetonitrile/n-hexane. The resulting acetonitrile solutions were evaporated to dryness. The residue was dissolved in methanol, and subjected to LC/MS. The LC separation was performed on a Wakosil-II 3C18HG column (150῍3 mm i.d.) in isocratic mode with 0.05῎ trifluoroacetic acidῌacetonitrile (80 : 20) as a mobile phase at a flow rate of 0.4 mL/min. The MS detection was performed in the selected ion recording (SIR) mode, with detection of the MῌH ῌ ion of ractopamine (m/z 302) produced by electrospray ionization (ESI). The mean recoveries of the drug from swine muscle (0.01 mg/g fortified), fat (0.01 mg/g fortified) and liver (0.04 mg/g fortified) were 99.7῎, 99.5῎ and 100.8῎, and those from cattle samples were 108.3῎, 97.0῎ and 109.4῎, respectively. The relative standard deviations (RSDs) ranged from 0.1῎ to 9.5῎. The limit of quantification (LOQ) of the drug was 1 ng/g.

Ractopamine as a metabolic modifier feed additive for finishing pigs: a review

“…In order to monitor the illegal use of ractopamine, it is necessary to develop proper residue detection methods in swine tissues, feeds, and urine. Recent researches have suggested instrumental methods to detect these residues (Sakai et al 2007;Shen et al 2007;Zhang et al 2009;Zhai et al 2011), but no mention of ractopamine-withdrawal period for finishing pigs were made. In this way, further studies are required to determine whether consumer safety can be assured without applying a ractopamine-withdrawal period.…”

Effects of ractopamine plus amino acids on growth performance, carcass characteristics, meat quality, and ractopamine residues of finishing pigs

“…Most of the studies available on RAC use growth performance traits (Aalhus et al, 1990;Barker et al, 2005;Ross et al, 2011) or carcass measurements, meat quality and sensory attributes (Fernández-Dueñas, 2008;Kutzler et al, 2011), but few studies have reported tissue residue concentrations (i.e., muscle and liver). Some studies have focused on comparing techniques to quantify residues (Shishani et al, 2003;Qiang et al, 2007;Sakai et al, 2007), but to our knowledge, there are no complete studies using RAC that reported live animal performance, carcass and meat characteristics, and residue concentrations in target tissues. Thus, the objective of this study was to investigate the effects of the addition of RAC plus amino acids on growth performance, carcass characteristics, cuts yield, meat quality, sensory attributes and residues in liver and muscle of finishing pigs.…”

Ractopamine: analytical method validation; and the detection in loin, tissues and urine of pigs fed meat and bone meal containing this growth promoter

“…Some studies do not use the step of hydrolysis with β-glucuronidase enzyme in the determination of RAC in tissues [14,[30][31][32]. In this work, we still reinforce the use of it, because RAC glucuronide metabolites A-F ( Fig.…”